The Federal Emergency Management Agency recently rejected the New York State Department of Environmental Conservation’s request to fund a $690 million outflow pipe that would stretch from the Bay Park Sewage Treatment Plant, in East Rockaway, three miles into the Atlantic Ocean. The decision makes little sense.

Nassau County has desperately needed the pipe for decades. Various lawmakers, most prominently County Legislator David Denenberg, a Democrat from Merrick, have fought for such a pipe for years, to no avail. The county, seemingly in a continuous fiscal crisis, has been unable to cobble together the funds needed to construct the pipe.

We saw the result during Superstorm Sandy. The storm overran the plant, causing its vital systems to collapse, sending 100 million gallons of raw sewage flowing into Hewlett Bay in the first 44 hours after the storm. Would a pipe have prevented such an enormous spill? Perhaps not –– but there is little doubt that it would have helped to alleviate it.

Bay Park has undergone and is undergoing hundreds of millions of dollars in repair work to restore and upgrade it in order to withstand the next big storm that comes our way. We should build the outflow pipe while work is under way on the plant –– not later. The federal government should agree to fund it –– if not entirely, at least substantially.

No matter what, the plant will need the pipe, because the state is expected to hand down tougher nitrogen release standards to protect our coastal bays. FEMA said it would not fund the pipe because those standards were not yet in place when Sandy struck in 2012.

True, but here’s the thing: Bay Park is an ancient plant, with ancient technology. It was built in 1955, a full decade and a half before passage of the federal Clean Water Act. Its outflow pipe releases partially treated, nitrogen-rich wastewater into Reynolds Channel, a half-mile north of Long Beach. Bay Park, which processes 40 percent of Nassau County’s sewage, releases 70 million gallons of wastewater into the channel per day.